Theory of long-lived nuclear spin states in methyl groups and quantum-rotor induced polarisation

TY - JOUR

T1 - Theory of long-lived nuclear spin states in methyl groups and quantum-rotor induced polarisation

AU - Dumez, Jean Nicolas

AU - Håkansson, Pär

AU - Mamone, Salvatore

AU - Meier, Benno

AU - Stevanato, Gabriele

AU - Hill-Cousins, Joseph T.

AU - Roy, Soumya Singha

AU - Brown, Richard C D

AU - Pileio, Giuseppe

AU - Levitt, Malcolm H.

PY - 2015/1/1

Y1 - 2015/1/1

N2 - Long-lived nuclear spin states have a relaxation time much longer than the longitudinal relaxation time T1. Long-lived states extend significantly the time scales that may be probed with magnetic resonance, with possible applications to transport and binding studies, and to hyperpolarised imaging. Rapidly rotating methyl groups in solution may support a long-lived state, consisting of a population imbalance between states of different spin exchange symmetries. Here, we expand the formalism for describing the behaviour of long-lived nuclear spin states in methyl groups, with special attention to the hyperpolarisation effects observed in 13CH3 groups upon rapidly converting a material with low-barrier methyl rotation from the cryogenic solid state to a room-temperature solution [M. Icker and S. Berger, J. Magn. Reson. 219, 1 (2012)]. We analyse the relaxation properties of methyl long-lived states using semi-classical relaxation theory. Numerical simulations are supplemented with a spherical-tensor analysis, which captures the essential properties of methyl long-lived states.

AB - Long-lived nuclear spin states have a relaxation time much longer than the longitudinal relaxation time T1. Long-lived states extend significantly the time scales that may be probed with magnetic resonance, with possible applications to transport and binding studies, and to hyperpolarised imaging. Rapidly rotating methyl groups in solution may support a long-lived state, consisting of a population imbalance between states of different spin exchange symmetries. Here, we expand the formalism for describing the behaviour of long-lived nuclear spin states in methyl groups, with special attention to the hyperpolarisation effects observed in 13CH3 groups upon rapidly converting a material with low-barrier methyl rotation from the cryogenic solid state to a room-temperature solution [M. Icker and S. Berger, J. Magn. Reson. 219, 1 (2012)]. We analyse the relaxation properties of methyl long-lived states using semi-classical relaxation theory. Numerical simulations are supplemented with a spherical-tensor analysis, which captures the essential properties of methyl long-lived states.

UR - http://www.scopus.com/inward/record.url?scp=84923809068&partnerID=8YFLogxK

U2 - 10.1063/1.4906273

DO - 10.1063/1.4906273

M3 - Article

AN - SCOPUS:84923809068

VL - 142

SP - 1

EP - 14

JO - The Journal of Chemical Physics

JF - The Journal of Chemical Physics

SN - 0021-9606

IS - 4

M1 - 044506

ER -